To connect your ConvertKit account, you will need the following:
A ConvertKit API key
A ConvertKit API secret key.
Get the required Data
Log in to your ConvertKit account
Click on your Account (top right corner) and choose the Settings link.
Click on the Advanced link.
Copy the API Key and click the Show button to reveal the API Secret Key.
Connect ConvertKit with Divi's Email Opt-in module
Open the Email Opt-in module Settings modal window.
Go to the Content Tab → Email Account.
Select the ConvertKit from the provider's list.
Click on the Add button.
Fill in the following fields:
Name - It can be anything you want. For example, you can use
my-convertkit
API Key - Paste the ConverKit API key.
API Secret - Paste the ConverKut API Secret.
Click on the Submit button.
Choose the ConverKit list you want to use.